linux-next/arch/arm/mm/cache-fa.S
Linus Walleij 7b749aad1f ARM: 9393/1: mm: Use conditionals for CFI branches
Commit 9385/2 introduced a few branches inside function
prototypes when using CFI in order to deal with the situation
where CFI inserts a few bytes of function information in front
of the symbol.

This is not good for older CPUs where every cycle counts.

Commit 9386/2 alleviated the situation a bit by using aliases
for the cache functions with identical signatures.

This leaves the coherent cache flush functions
*_coherent_kern_range() with these branches to the corresponing
*_coherent_user_range() around, since their return type differ and
they therefore cannot be aliased.

Solve this by a simple ifdef so at least we can use fallthroughs
when compiling without CFI enabled.

Link: https://lore.kernel.org/linux-arm-kernel/Zi+e9M%2Ff5b%2FSto9H@shell.armlinux.org.uk/

Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2024-05-07 10:30:24 +01:00

248 lines
6.2 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/mm/cache-fa.S
*
* Copyright (C) 2005 Faraday Corp.
* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*
* Based on cache-v4wb.S:
* Copyright (C) 1997-2002 Russell king
*
* Processors: FA520 FA526 FA626
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/cfi_types.h>
#include <asm/assembler.h>
#include <asm/page.h>
#include "proc-macros.S"
/*
* The size of one data cache line.
*/
#define CACHE_DLINESIZE 16
/*
* The total size of the data cache.
*/
#ifdef CONFIG_ARCH_GEMINI
#define CACHE_DSIZE 8192
#else
#define CACHE_DSIZE 16384
#endif
/* FIXME: put optimal value here. Current one is just estimation */
#define CACHE_DLIMIT (CACHE_DSIZE * 2)
/*
* flush_icache_all()
*
* Unconditionally clean and invalidate the entire icache.
*/
SYM_TYPED_FUNC_START(fa_flush_icache_all)
mov r0, #0
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
ret lr
SYM_FUNC_END(fa_flush_icache_all)
/*
* flush_user_cache_all()
*
* Clean and invalidate all cache entries in a particular address
* space.
*/
SYM_FUNC_ALIAS(fa_flush_user_cache_all, fa_flush_kern_cache_all)
/*
* flush_kern_cache_all()
*
* Clean and invalidate the entire cache.
*/
SYM_TYPED_FUNC_START(fa_flush_kern_cache_all)
mov ip, #0
mov r2, #VM_EXEC
__flush_whole_cache:
mcr p15, 0, ip, c7, c14, 0 @ clean/invalidate D cache
tst r2, #VM_EXEC
mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
mcrne p15, 0, ip, c7, c5, 6 @ invalidate BTB
mcrne p15, 0, ip, c7, c10, 4 @ drain write buffer
mcrne p15, 0, ip, c7, c5, 4 @ prefetch flush
ret lr
SYM_FUNC_END(fa_flush_kern_cache_all)
/*
* flush_user_cache_range(start, end, flags)
*
* Invalidate a range of cache entries in the specified
* address space.
*
* - start - start address (inclusive, page aligned)
* - end - end address (exclusive, page aligned)
* - flags - vma_area_struct flags describing address space
*/
SYM_TYPED_FUNC_START(fa_flush_user_cache_range)
mov ip, #0
sub r3, r1, r0 @ calculate total size
cmp r3, #CACHE_DLIMIT @ total size >= limit?
bhs __flush_whole_cache @ flush whole D cache
1: tst r2, #VM_EXEC
mcrne p15, 0, r0, c7, c5, 1 @ invalidate I line
mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
tst r2, #VM_EXEC
mcrne p15, 0, ip, c7, c5, 6 @ invalidate BTB
mcrne p15, 0, ip, c7, c10, 4 @ data write barrier
mcrne p15, 0, ip, c7, c5, 4 @ prefetch flush
ret lr
SYM_FUNC_END(fa_flush_user_cache_range)
/*
* coherent_kern_range(start, end)
*
* Ensure coherency between the Icache and the Dcache in the
* region described by start. If you have non-snooping
* Harvard caches, you need to implement this function.
*
* - start - virtual start address
* - end - virtual end address
*/
SYM_TYPED_FUNC_START(fa_coherent_kern_range)
#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
b fa_coherent_user_range
#endif
SYM_FUNC_END(fa_coherent_kern_range)
/*
* coherent_user_range(start, end)
*
* Ensure coherency between the Icache and the Dcache in the
* region described by start. If you have non-snooping
* Harvard caches, you need to implement this function.
*
* - start - virtual start address
* - end - virtual end address
*/
SYM_TYPED_FUNC_START(fa_coherent_user_range)
bic r0, r0, #CACHE_DLINESIZE - 1
1: mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c5, 6 @ invalidate BTB
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
mcr p15, 0, r0, c7, c5, 4 @ prefetch flush
ret lr
SYM_FUNC_END(fa_coherent_user_range)
/*
* flush_kern_dcache_area(void *addr, size_t size)
*
* Ensure that the data held in the page kaddr is written back
* to the page in question.
*
* - addr - kernel address
* - size - size of region
*/
SYM_TYPED_FUNC_START(fa_flush_kern_dcache_area)
add r1, r0, r1
1: mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D line
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
ret lr
SYM_FUNC_END(fa_flush_kern_dcache_area)
/*
* dma_inv_range(start, end)
*
* Invalidate (discard) the specified virtual address range.
* May not write back any entries. If 'start' or 'end'
* are not cache line aligned, those lines must be written
* back.
*
* - start - virtual start address
* - end - virtual end address
*/
fa_dma_inv_range:
tst r0, #CACHE_DLINESIZE - 1
bic r0, r0, #CACHE_DLINESIZE - 1
mcrne p15, 0, r0, c7, c14, 1 @ clean & invalidate D entry
tst r1, #CACHE_DLINESIZE - 1
bic r1, r1, #CACHE_DLINESIZE - 1
mcrne p15, 0, r1, c7, c14, 1 @ clean & invalidate D entry
1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
ret lr
/*
* dma_clean_range(start, end)
*
* Clean (write back) the specified virtual address range.
*
* - start - virtual start address
* - end - virtual end address
*/
fa_dma_clean_range:
bic r0, r0, #CACHE_DLINESIZE - 1
1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
ret lr
/*
* dma_flush_range(start,end)
* - start - virtual start address of region
* - end - virtual end address of region
*/
SYM_TYPED_FUNC_START(fa_dma_flush_range)
bic r0, r0, #CACHE_DLINESIZE - 1
1: mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D entry
add r0, r0, #CACHE_DLINESIZE
cmp r0, r1
blo 1b
mov r0, #0
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
ret lr
SYM_FUNC_END(fa_dma_flush_range)
/*
* dma_map_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
SYM_TYPED_FUNC_START(fa_dma_map_area)
add r1, r1, r0
cmp r2, #DMA_TO_DEVICE
beq fa_dma_clean_range
bcs fa_dma_inv_range
b fa_dma_flush_range
SYM_FUNC_END(fa_dma_map_area)
/*
* dma_unmap_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
SYM_TYPED_FUNC_START(fa_dma_unmap_area)
ret lr
SYM_FUNC_END(fa_dma_unmap_area)